Man I think that would be frustrating, open a tin after 5-10 years and meh ..
It is, but it's also part of it.
With aging, you just never know.
There are some general things that are true most of the time.
For example, aromatics don't improve with age, at least the cavendish based ones. If anything the flavoring mellows over time. I guess that could be good or bad depending on your personal preference.
Burleys don't do much with age.
Latakia mellows over time.
Virginias are where it's at. To me (again, this is my opinion), Virginia based blends are the only ones worth aging.
Now these opinions only apply to aging to improve the tobacco. There are obviously other reasons to have a lot stowed away in the cellar. Cost is one. Tobacco is as cheap as it ever will be, and stocking up when you can afford to do so is wise.
Also favorite blends sometimes go away. I've only been smoking a pipe for 10 years and it's happened 3 times to me. First McClelland, then Orlik Dark Strong Kentucky, and now HH Old Dark Fired.
I was lucky enough to stock up on a couple of them, but I only have one tin of Dark Strong Kentucky.